Doenecke, Justus D.
Hoover Institution Press, 1981
Buku Teks
Hornbeck, Stanley K.
World Peace Foundation, 1942
Buku Teks
Freeman, Stanley K.
John Wiley & Sons, 1974
Buku Teks
edited by M.J. Toswell and E.M. Tyler
Routledge, 1996
Buku Referensi
Eitzen, D. Stanley, author
Allyn and Bacon, 1989
Buku Teks